The present invention relates to an electrophotographic color image forming apparatus in which a plurality of charging means, image exposure means and developing means are arranged around the circumferential surface of an image forming member, and toner images are formed and superimposed while the image-forming member is rotated by a single rotation.
As an apparatus for forming a full color image, the following type of a color image forming apparatus is well known: each of a charging device, an image exposure device and a developing device is provided in the same number of sets as different component colors necessary to form a full color image around the circumferential surface of the image forming member, the steps of charging, imagewise exposing and developing are sequentially conducted for each component color so as to form and superimpose different color toner images during a single rotation of the image forming member, and the thus formed color toner image is transferred to a transfer material at one time.
The above apparatus has features that a color image formation speed is very fast and that it is possible to form a color image longer than the length of the circumferential surface of the image forming member, because the toner image formation for each color is successively started at a slight time delay after the start of the previous image formation.
However, in the above color image forming apparatus, since each of the charging devices, the image exposure device and the developing device is provided in plural sets around the circumferential surface of the image forming member, if the apparatus is to be constructed compactly, each device is inevitably positioned very close to others and the construction becomes complicated. As a result, there may be problems that maintenance works such as paper jam clearing, cleaning, part replacement require much time and labor.